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Converting Qbyte array to array and to double

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  • D Offline
    D Offline
    dziko147
    wrote on last edited by
    #3

    @artwaw thanks for your reply . Ok I will remove the Qstring .

    Also I get unreadable data like " 3.13891e-43 " for a array "0xff000000e0" .

    I use a online converter and give the same value .

    But there is a way to make it readable .

    thank you

    artwawA 1 Reply Last reply
    0
    • D dziko147

      @artwaw thanks for your reply . Ok I will remove the Qstring .

      Also I get unreadable data like " 3.13891e-43 " for a array "0xff000000e0" .

      I use a online converter and give the same value .

      But there is a way to make it readable .

      thank you

      artwawA Offline
      artwawA Offline
      artwaw
      wrote on last edited by
      #4

      @dziko147
      again: in the "else" part you have

      qDebug()  << "this is data"<< myDatadouble;
      QString DatatoString =QString::number(myData);
      

      where I think you should have

      qDebug()  << "this is data"<< myDatadouble;
      QString DatatoString =QString::number(myDatadouble);
      

      since you do not even set myData in that part. Hence your string contains rubbish, you don't even initialise the variable.

      For more information please re-read.

      Kind Regards,
      Artur

      1 Reply Last reply
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      • D Offline
        D Offline
        dziko147
        wrote on last edited by
        #5

        @artwaw yes in my code I have

        qDebug()  << "this is data"<< myDatadouble;
        QString DatatoString =QString::number(myDatadouble);
        

        just when i copying it i I was mistaken .

        I update my topic :)

        1 Reply Last reply
        0
        • D dziko147

          Hello , I get some data from a CAN Bus . So my data is some float and some double .

          What I did is :

          float myData;
          double myDatadouble;
          
                             QDataStream stream(data);
                              qDebug() << data.size() << " Data Data&size" ;
                             
                              if (data.size()== 5){
                                 quint8 byte;
                                  stream >> byte; // skip first byte
                        stream.setFloatingPointPrecision(QDataStream::SinglePrecision);
                                  stream >> myData; // read data
                                  qDebug()  << "this is data"<< myData ;
                                  QString DatatoString =QString::number(myData);
                                  Outputs[i]=DatatoString;
                              qDebug() << "In outputs data" << Outputs[i];
                              }
          else {
          
                             quint8 byte;
                              stream >> byte; // skip first byte
                                  stream.setFloatingPointPrecision(QDataStream::DoublePrecision);
                               stream >> myDatadouble; // read data
                              qDebug()  << "this is data"<< myDatadouble;
                              QString DatatoString =QString::number(myDatadouble);
                              Outputs[i]=DatatoString;
                              qDebug() << "In outputs data" << Outputs[i];
                              }              
                             
          
          

          I get only float converted , the double is usually "0" .

          thankyou

          CP71C Offline
          CP71C Offline
          CP71
          wrote on last edited by CP71
          #6

          @dziko147
          Hi,
          you have checked only if (data.size()== 5) in first if,
          Did you check in else that the data size is correct?
          I think no

          1 Reply Last reply
          0
          • D Offline
            D Offline
            dziko147
            wrote on last edited by
            #7

            @CP71 yes it return a size :8 byte

            CP71C 1 Reply Last reply
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            • D dziko147

              @CP71 yes it return a size :8 byte

              CP71C Offline
              CP71C Offline
              CP71
              wrote on last edited by
              #8

              @dziko147
              8! so doesn't you have a one spare byte in else as in float case?

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              • D Offline
                D Offline
                dziko147
                wrote on last edited by dziko147
                #9

                @CP71 said in Converting Qbyte array to array and to double:

                8! so doesn't you have a one spare byte in else as in float case?

                no I usually get frame started with FF .

                I mean than in the case of a float I get "FF + 4Byte data"

                In the case of a Double I get "FF +7Byte data "

                and here I skip the first byte

                                   quint8 byte;
                                    stream >> byte; // skip first byte
                
                CP71C 1 Reply Last reply
                0
                • D dziko147

                  @CP71 said in Converting Qbyte array to array and to double:

                  8! so doesn't you have a one spare byte in else as in float case?

                  no I usually get frame started with FF .

                  I mean than in the case of a float I get "FF + 4Byte data"

                  In the case of a Double I get "FF +7Byte data "

                  and here I skip the first byte

                                     quint8 byte;
                                      stream >> byte; // skip first byte
                  
                  CP71C Offline
                  CP71C Offline
                  CP71
                  wrote on last edited by CP71
                  #10

                  @dziko147 said in Converting Qbyte array to array and to double:

                  In the case of a Double I get "FF +7Byte data "

                  Sorry, but in double case I think you'd send 0xFF+8bytes, anyway I think your application tries read a double at 8 bytes

                  1 Reply Last reply
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                  • D Offline
                    D Offline
                    dziko147
                    wrote on last edited by
                    #11

                    @CP71 you are right :D

                    1 Reply Last reply
                    0
                    • D Offline
                      D Offline
                      dziko147
                      wrote on last edited by
                      #12

                      @CP71 now how can make it readable .
                      For example I get " 3.13891e-43 " for a array "0xff000000e0" .
                      please

                      CP71C 1 Reply Last reply
                      0
                      • D dziko147

                        @CP71 now how can make it readable .
                        For example I get " 3.13891e-43 " for a array "0xff000000e0" .
                        please

                        CP71C Offline
                        CP71C Offline
                        CP71
                        wrote on last edited by
                        #13

                        @dziko147
                        It is wrong!

                        https://www.binaryconvert.com/convert_double.html

                        As last time, I must go.
                        Sorry, bye

                        1 Reply Last reply
                        0
                        • D Offline
                          D Offline
                          dziko147
                          wrote on last edited by
                          #14

                          @CP71 as u like bro good bye

                          1 Reply Last reply
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